Chaga Mushroom

The ASCO Post’s Integrative Oncology series is intended to facilitate the availability of evidence-based information on integrative and complementary therapies sometimes used by patients with cancer. In this installment, Ting Bao, MD, DABMA, MS, and Jyothirmai Gubili, MS, explore the current research findings regarding the antioxidant and immunostimulatory effects of chaga mushroom, available in the form of teas and extracts. They note that clinical trials are needed to confirm such effects.

Ting Bao, MD, DABMA, MS

Jyothirmai Gubili, MS

Scientific Name:Inonotus obliquus

Common Names: Cinder conk, Birch conk, clinker polypore

Overview

Prevalent in cold climates, chaga mushroom grows on birch and other trees. It has been used as a folk remedy in Russia, the Baltics, and other northern European countries to treat various ailments, including digestive system disorders, ulcers, as well as cancer. The part used medicinally, known as the conk, consists of wood from the substrate tree and mycelium of the invasive fungus.

Although edible, chaga mushroom is not commonlyconsumed due to its bitter nature. Instead tea made from the whole mushroom is more popular. Chaga extracts are also marketed as supplements in the form of capsules, tablets, and teas for their antioxidant and immunostimulatory effects. Efforts are underway to develop cultivated substitutes of wild chaga due to overharvesting of natural reserves.1

OF NOTE

Patients and care teams should be aware of the possible risk of nephropathy associated with the use of changa mushroom and its interactions with antiplatelet or anticoagulant drugs as well as with hypoglycemic agents.

Studies in murine models indicate that a chaga extract (0.1, 1.0, and 10.0 mg, administered orally once daily for 21 days; 20 μg or 200 μg, given intraperitoneally on days 0 and 21) inhibited allergen-induced systemic anaphylactic shock. Significant reductions were observed in immunoglobulin E production (P < .01), with intraperitoneal administration reported to be more effective than the oral route.9

Jun J. Mao, MD, MSCE

Another oral extract (50 and 100 mg/kg administered for 7 days) significantly improved learning and memory (P < .01) in scopolamine-induced amnesic mice, likely through its antioxidant property and also by inhibiting acetylcholinesterase.10

And in an experimental colitis model, similar doses of 50 mg/kg and 100 mg/kg, twice a day, for 14 days showed anti-inflammatory effects by suppressing the inflammatory mediators tumor necrosis factor–alpha and inducible NO synthase together with interleukin-1 beta.11

In a single case report, oxalate nephropathy was associated with ingestion of chaga mushroom powder (4–5 teaspoons daily for 6 months), in a 72-year-old woman with liver cancer.21

Herb-Drug Interactions

Antiplatelet oranticoagulant drugs: Chaga extract inhibited platelet aggregation in a murine model.5 It may also have synergistic effects when used with anticoagulant/antiplatelet drugs. However, the clinical relevance of these findings is not known.

Hypoglycemic agents: In vitro, chaga had additive effects in lowering blood sugar levels.6 Again, the clinical significance of this finding is yet unknown.

Summary

Chaga mushroom tea and extracts have been marketed for their antioxidant and immunostimulatory effects, mainly supported by in vitro and in vivo studies. However, clinical trials are needed to confirm such effects. Patients and care teams should be aware of the possible risk of nephropathy associated with the use of chaga and its interactions with antiplatelet or anticoagulant drugs as well as with hypoglycemic agents. ■

DISCLOSURE: Dr. Bao was on the advisory board of Eisai. Ms. Gubili reported no conflicts of interest.